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W. E. PRINDLE.

ROTARY DRIER.

APPLICATION FILED SEPT. 2, 1914.

Patented July 29, 1919.

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I I STATES PATEN WILLIAM E. PRINDLE, OF LONDON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO'THE BUCKEYE DRYER COMPANY, OF COLUMBUS, OHIO, A CORPORATION.

' ROTARY DRIER.

Specification of Letters'latent. P t ted July 29, 1919.

I Application filed September 2, 1914. Serial No. 859,889.

To all whom it may concern:

Be it lmown that I, WILLIAM E. PRINDLE, a citizen of the United States, residing at London, in the county of Madison and State of Ohio, have invented certain new and useful Improvements in Rotary Driers, of which the following is a specification.

My invention relates generally to a mechanical rotary drier of the type used particularly for the commercial drying of wet materials. I

The main object of my invention resides in'the provisionof a structure for economically and efliciently withdrawing the moist vapors produced by the application of heat to the moist material. This application of heat or the heat interchange between the hot air and the moist material should be made in a manner that the material being dried, is not scorched or burned, but still possesses a required degree of dryness. My preferred manner of accomplishing this is by the introduction of hot air to the imaterial at a point near the discharge end of-the drier and causing this air to flow in a direction opposite tothe direction of travel of the material itself. In this manner, theheated air constantly comes into engagement with material cooler than itself and it will consequently become moisture laden before it is exhausted. It is true that the capacity of air as regards its power ofabsorbing and retaining moisture varies with its temperature,

' the lower the temperature, the less amount of moisture it is able to carry. However, as the air is cooled, it passes toward the exhaust end of the drier as far as the air itself is concerned, or the entrance end of the drier with respect to thematerial,consequently, I am practically assured that the air being exhausted will be thoroughly saturated and, therefore, more fully perform its function than should it be only partially saturated, thereby requiring a greater amount of air.

Stated more specifically, my invention contemplates the drying of material in the manner specified above by the combined action of direct and radiatedheat. This I accomplish by providing an inner and exterior cylinder, the inner'cylinder communicating at its rear end with an air producerand projecting into the rear portion of the outer cylinder a distance to prevent direct contact of the heated gases with the material after it has passed through the outer cylinder a distance to be in a comparatively dry state; By this arrangement, the final stateof drying may be accomplished by the radiated heat from the inner cylinder and consequently the material will not become scorched or burned. v

Another object of my invention resides in so constructing my drier that the material itself as it approaches its delivery end in a comparatively. dry state, will not become scorched or burned. 7

Further objects of myinvention will ap pear from a further detailed description of the accompanying sheet of drawing, in which similar characters of reference designate-corresponding parts and in which:

The figure is a central Vertical section through my drier.

In this drawing, the outer cylindrical casing forming an important element of my drier, is designated generally as 1, this casing being. preferably mounted so as to rest at an incline to the horizontal and is directly supported by means of annular tires 2 upon rollers 3 preferably located 'a suitable distance at eachside of a central vertical plane and being mounted upon abutments 4. Ro-

tary motion is imparted'tothe outer cylin- 1 der 1 by means of .an annular spur gear 5 carried at one end, this spur gear being designed to meshwith a spur pinion '6 upon a shaft 7, this shaft 7 being driven in any desired manner from any suitable source of power supply. The interior of the outer cylinder 1 is provided-with a plurality'of lifting blades formed by longitudinally extending angles 9 symmetrically spaced whose radial legs are provided at suitable intervals to present a staggered relation with plates 10. In the rear portion of this outer cylinder there is mounted an inner cylinder 11, preferably extending toward the inlet portion of the outer cylinder a distance only to approximately cover that portion which is normally occupied by the dried material as it passes to a conveyer 12 located below the rear open end of this .outer cylinders The inner cylinder is mounted to rotate w-iththe outer cylinder by means of arms 13 and 14 arranged in spider relation. It will benoted that the arms 13 are mounted practically at the rear end of this outer cylinder and are rigidly heldin place by a plurality "of rivets shown. Inord'er that-there'may. be the required compensation between thetwo cylinders due to'a difference in expansion and contraction, I v have pivotally attached the spider arms 14: to both the cylinders by means of single rivets or bolts as indicated at 15. The forward end of the inner cyli-v inder is further-provided with a fiaringhood, portion 16', the flare being provided to prevent the access of material .to itsinterior;

while this material is being cascaded due to the rotation of thedrieras a whole. during its normal'operation. In orderthat the material asitleaves the outercylinder, may not become abnormally heated, I have lined the interior of the" inner cylinder with refractory material 17which may be in the nature of arch or wedge brick. It will further be noted F that the entire outer surface of this inner cylinder is solid andi direct communication of the incoming air from the heat producer to bepresently described, withthe material passing out, is not provided, the remaining drying operation 7 being effected throughradiation only. 7

Located adjacent thc delivery endof the drier :asa' whole, is the hot airproducer designated generally-lat: 18, this producer being shown as being provided with the usual type of grate bars 19 andan outlet fine 20.

flue pipe 21 connects the outlet 20 with the rear end o-f the inner'cy linder; 11, this flue pipe being also preferably linedwith refractory material as isindicated at- 22.

r The joining between the fluepipe and the inner-cylinder iseffected by means of the Z' shaped bearingmember 23 carried by the 'fluepipe itselffiandmhe angle-bearing member 24c carried uponthe endrof the cylinder.

This I flue pipe is designed; to be stationary as regards rotary movement of. the. drier as whole and issuitably: supported upon standards '25. The distance between the heat'producer 1 8 and the discharge end of the drier as-Ma whole is closedto theatmosphere toprevent escape of the dry material in the form of dust byxmeans; OfIZLSlJZLlJlOIlELIY covering 26 shaped to conformztothe shape ofthe furnace atone end and; rigidly attached to a hood'27- rigidly mounted upon standards 28 1 and being so formed to. carry the conveyer-12'previously referred'to and to close the rotating open end of the outer cylinder 1;

-The wet" material is introduced to the front end of the outer cylinder by means-of a feed spout'29 rigidly mountediin connection with the vapor bonnet 30. This vapor bonnet forms the; stationary portion for "closing the front endof the outer cylinder-V1 and is so formed that it has. rotating contact with the front ring- 31' rigidlyv mounted on: the I cylinder itself. The vapor bonnet 50 has 'a Y central opening a formed therein to 6 5 which is adapted to be attached the fan conthe delivery end.-.

n'ection32 leading to. any suitable type of suctiondevice or blower element as is indicated at 38. I a V The operation of my device is as follows:

"Rotation is given the outer cylinder 1 by anysuitable type of drive mechanism after the heat producing unit has been set in operation and likewise the suction device 33. The wet material is then introduced-to the interior of the-outer: cylinder by its passage through the feed spout 29 and the rotation of this outer cylinder-causing cascading of the materialz dire to-zthe lifting blade structure carried i by: this cylinder; Because of.v the inclination of the. drier. as a; whole,

ward the discharge end and'zultimately-into the conveyerf' Ho:wever, inl the meantime, heated 1 gases; pass 'ifrorne the; heatproducer out thIOllgll'ztllG innercylinder 11, :In

this wet material will:be.agraduallyrfed*toorderrthattthis innerlrcylinder may; not bemg its-lash stage; of dryingn If any further 7 moisture is carried by this material, the high degree of this heat-wil'l-naturally cause it to (turn into vapor, while the direct contact of the. heated; airxpassing outr through the open. end, of; the innericylindenz; causes a similar action upon the material before it reaches, theycompletely vdried: stage; The suction 1 device :33 causes.-

indueed flow of this: air and inaturally; thezhottest- :airrcoming into contact with the'driest materialvcarries away all the remaining; moisture. However, as this air, passes-- to, the exhaust device, it becomes gradually. cool due a to; its contact with the lnoreased moisture laden: material.

Itis known thatiiaair at a higher temperature air at: a: lower; temperature andiin ithisemanner, I am assured; that: thepalr beingexhausted, under fproperrregulations, e-w l be cancarry-more moisture in suspensiontha-n thoroughly r saturated.- Should this passing vair become saturated before it; enters the exhaust device, no -harm will follow because the only result can be that it willprecipitate itsv excess moisture and this v; precipitation naturally occurs; atthe" entrance endofithe drier. and will 5 again-beturnedinto a vapor as the material; progresses;- toward thedeliveryrend t0;en'counter the war-men gases.-

5 It will thus be apparent, thatiI? have-providedan :extremely eiiicient-device wherein I amyassured' ofperfect operation of; the; de-

vice to obtainrperfectly dry-r material-tor material in 1 the stages of dryness desired at What I claim is 1. A rotary drier comprising an outer cylinder provided adjacent its front end with a hot air outlet, means for feeding material into the front end of said cylinder, a hot air producer, an inner cylinder within and in communication with said outer cylinder and communicating at its rear end with said producer, a refractory lining for said inner cylinder, said inner cylinder extending into the rear portion only of said outer cylinder a distance to prevent direct contact of the heated gases With the material after it has passed through said outer cylinder a distance to be in a comparatively dry state, and a suction device connected to said hot air outlet to cause a flow of hot air in a direc tion opposite to the travel of the material through said outer cylinder.

2. A rotary drier comprising an outer cylinder provided with a hot air outlet at its front end, a feed spout communicating with the front end of said cylinder, a hot air producer, an inner cylinder open at its front within said outer cylinder and communicating with said producer at its rear end, a refractory lining for the interior of said cylinder, and a suction device connected to said hot air outlet arranged to cause a flow of air out of the front end of said outer cylinder in a direction opposite to the travel of material therethrough.

3. A rotary drier comprising an outer cylinder provided with a hot air outlet at its front end, a feed spout communicating &

with the front end of said cylinder, a hot air producer, an inner cylinder open at its front within said outer cylinder and communicating with said producer at its rear end, said inner cylinder projecting into said outer cylinder only a slight distance beyond its discharge end, a refractory lining for the inner surface of said inner cylinder, and a suction device connected to said hot air outlet arranged to cause a flow of air out of the front end of said outer cylinder in a direction opposite to the travel of material therethrough.

4. A rotary drier comprising an outer cylinder provided with a hot air outlet at its front end, an inner cylinder open at its front end within the rear portion only of said outer cylinder, the side walls of said inner cylinder being closed to prevent direct contact of the material with the heated air passing therethrough, a refractory lining for the interior of said inner cylinder, a heat producer communicating with the rear end of said inner cylinder, and a suction device communicating with said hot air outlet opening in said outer cylinder to cause a flow of the heated air in a direction opposite to the travel of the material.

In testimony whereof I alfix my signature in presence of two witnesses.

WILLIAM E. PRINDLE.

Witnesses:

J FOSTER, H. L. Fos'rnn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

